Neck injury mitigation systems and methods

ABSTRACT

Seat belt systems and inflatable airbags can be used to mitigate the potential for injury to an occupant&#39;s neck. The seat belt systems provide for moderating the seat belt loads acting on the occupant to allow an improved synchronization of the occupant torso and head rebound timing, which in turn limits head and torso differential loading (frontal whiplash) and therefore occupant neck loads and neck, based on the position of the occupant, loads on the seatbelt, or a predetermined time in the crash event. Airbags are also provided with a sloped impact face. Additionally, airbags are also provided with a relatively flat top portion.

TECHNICAL FIELD

The present disclosure relates generally to the field of automotivesafety systems. More specifically, the present disclosure relates toinflatable airbag cushions and also to their use with seatbelt restraintsystems.

BRIEF DESCRIPTION OF THE DRAWINGS

The present embodiments will become more fully apparent from thefollowing description and appended claims, taken in conjunction with theaccompanying drawings. Understanding that the accompanying drawingsdepict only typical embodiments, and are, therefore, not to beconsidered to be limiting of the disclosure's scope, the embodimentswill be described and explained with specificity and detail in referenceto the accompanying drawings.

FIG. 1A is a side view of an occupant and a seat belt system duringretractor pretensioner loading phase or phase 1.

FIG. 1B is a side view of an occupant, a seat belt system and an airbagduring ride down induced loading or phase 2.

FIG. 1C is a side view of an occupant, a seat belt system and an airbagduring arrest and transition induced loading or phase 3.

FIG. 1D is a side view of an occupant, a seat belt system and an airbagduring rebound induced loading or phase 4.

FIG. 1E is a side view of an occupant, a seat belt system and an airbagduring rebound impact loading or phase 5.

FIG. 2 a front view of an occupant on a seat that shows a seatbeltsystem.

FIG. 3 a front view of an occupant on a seat that shows another seatbeltsystem.

FIG. 4 a front view of an occupant on a seat that shows an additionalseatbelt system.

FIG. 5 a front view of an occupant on a seat that shows yet anotherseatbelt system.

FIG. 6A is a graph that shows the load step down of a seatbelt system asmeasured at F₁.

FIG. 6B is a graph that shows the load step down of another seatbeltsystem as measured at F₁.

FIG. 6C is a graph that shows the load step down of an additionalseatbelt system as measured at F₁.

FIG. 7A is a perspective view of an airbag as shown in FIGS. 1A-1E.

FIG. 7B is a side view of the airbag shown in FIG. 7A.

FIG. 8 is a side view of a dummy, a seat belt system and the airbagcushion depicted in FIGS. 7A-7B.

FIG. 9 is a side view of another embodiment of an airbag, which has asloped impact face.

FIG. 10 is a side view of a dummy corresponding in size to AF05 andanother dummy corresponding in size to AM50, a seat belt system and theairbag cushion depicted in FIG. 9.

FIG. 11A is a side view of an occupant during ride down induced loading,a seat belt system and the airbag shown in FIG. 10.

FIG. 11B is a side view of an occupant after arrest and transitioninduced loading, a seat belt system and the airbag shown in FIG. 10.

FIG. 12 is a side view of an airbag cushion featuring a sloped impactface and a flat top portion.

FIG. 13 is a side view of a dummy, a seat belt system and the airbagcushion depicted in FIG. 12.

FIG. 14 is chart showing test data of a system as shown in FIG. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

It will be readily understood that the components of the embodiments asgenerally described and illustrated in the figures herein could bearranged and designed in a wide variety of different configurations.Thus, the following more detailed description of various embodiments, asrepresented in the figures, is not intended to limit the scope of thedisclosure, as claimed, but is merely representative of variousembodiments. While the various aspects of the embodiments are presentedin drawings, the drawings are not necessarily drawn to scale unlessspecifically indicated.

The phrases “connected to,” “coupled to” and “in communication with”refer to any form of interaction between two or more entities, includingmechanical, electrical, magnetic, electromagnetic, fluid, and thermalinteraction. Two components may be coupled to each other even thoughthey are not in direct contact with each other. The term “abutting”refers to items that are in direct physical contact with each other,although the items may not necessarily be attached together.

Inflatable airbag systems are widely used to minimize occupant injury ina collision scenario. Airbag modules have been installed at variouslocations within a vehicle, including, but not limited to, the steeringwheel, the instrument panel, within the side doors or side seats,adjacent to roof rail of the vehicle, in an overhead position, or at theknee or leg position. In the following disclosure, “airbag” may refer toan inflatable curtain airbag, overhead airbag, front airbag, or anyother airbag type.

Front airbags are typically installed in the steering wheel andinstrument panel of a vehicle. During installation, the airbags arerolled, folded, or both, and are retained in this packaged configurationbehind a cover. During a collision event, vehicle sensors trigger theactivation of an inflator, which rapidly fills the airbag with inflationgas. Thus the airbag rapidly changes configurations from the packagedconfiguration to an expanded configuration.

The systems, methods and airbags disclosed herein enable an occupant ofa vehicle to have a reduced risk of injury in the event of a crash. Thesystems and methods use a seat belt system, which has multiplefunctions. One function of the seat belt system is to be activatedbefore the airbag is activated so that the seat belt system providespretensioning to the seatbelt. Another function of the seatbelt systemis to be activated, after deployment of an airbag, to moderate therestraint loads upon an occupant at the critical time as the occupanttransitions into rebound. Moderation of belt loads as an occupanttransitions into rebound enables an improved synchronization of theoccupant torso and head rebound timing which in turn limits head andtorso differential loading (frontal whiplash) and therefore occupantneck loads and neck injuries. The moderation of belt loads applied tothe occupant is initiated based on the design of the particular system.For example, the moderation of the belt loads may be initiated orprompted based on the position or location of the occupant, based on adesignated time after an impact is sensed or other triggers that arerelative to reducing the occupant's velocity relative to the velocity ofthe vehicle. Factors that affect these triggers include the crashseverity, the size of the occupant, the speed of the vehicle, etc. Suchfactors would cause the timing of the initiation of the moderation ofthe belt load to vary.

FIGS. 1A-1E illustrate one embodiment during a collision taken at fivedifferent moments to show five distinct phases of the location of theoccupant 80 or crash dummy 80, particularly the neck behavior, as theoccupant interacts with the seatbelt system 110 and airbag 160. Inaddition to airbag 160, other airbags are disclosed herein that can beused in conjunction with the methods and systems.

FIG. 1A shows the retractor pretensioner loading phase. This phaseoccurs at a moment after an impact has been sensed up to about 40milliseconds after sensing the impact. As shown by direction arrow,D_(S), retracting the seatbelt 112 through the action of pretensioningcauses the occupant's torso to be pulled back, as shown by directionarrow, D_(T), toward backrest 92. More specifically, the occupant hasbeen pulled by seatbelt 112 such that the occupant's torso is againstbackrest 92 and the occupant's hips are against the lower portion ofbackrest 92 where backrest 92 joins base 94. The occupant is pulled inFIG. 1A due to the action of a seatbelt retractor pretensioner (notshown), which is in its loading phase. Such a pretensioner may, forexample, be driven by a microgas generator. As the occupant's torso ismoved firmly back into the seat, as shown in FIG. 1A, the occupant'shead moves in the opposite direction and the occupant's neck is placedin negative shear.

FIG. 1B shows an occupant during ride down induced loading. This phaseoccurs after airbag 160 has deployed. At this point the occupant andrestraint system are experiencing the vehicle's deceleration pulse. Asthe occupant rides down into the restraint system, airbag vents and seatbelt load limiter (not shown), such as a fold sewn into the beltwebbing, or an energy management mechanism contained in the seatbeltretractor, operate to moderate the loads applied to the occupant when acertain amount of force is applied to belt 112. This permits theoccupant's torso, as shown by direction arrow, D_(T), to move away frombackrest 92. As a result of the torso penetrating the airbag 160, thecushion becomes stiff and the occupant's head is moved backward towardbackrest 92, as shown by direction arrow, D_(H). The rearward movementof the occupant's head results in less penetration of airbag 160 byoccupant's head as compared with occupant's torso and the neck is placedin positive shear.

FIG. 1C shows an occupant during arrest and transition induced loading.In this third phase, seatbelt 112 has been stretched to its limit anddue to the stored elastic energy in the seatbelt webbing is ready topropel the occupant rearward in vehicle. More particularly, the torsoreaches a fully arrested state before the head and rebounds back towardthe backrest 92, as shown by direction arrow, D_(T), while the headcontinues to move forward, as shown by direction arrow, D_(H), and isstill penetrating airbag 160. However, the severity of this transitionloading on the neck is diminished by moderating the seatbelt restraintloads upon the occupant at the point at which the torso reaches a pointof maximum forward displacement. Moderating belt loads at this criticaltime enables an improved synchronization of the occupant torso and headrebound timing by reducing the severity with which the torso entersrebound. This in turn limits head and torso differential loading(frontal whiplash) and therefore occupant neck loads and neck injuries.Because the transition induced loading is less severe than the loadingwould be without moderating belt loads, the occupant's head is notrapidly recoiled in a rearward direction and the occupant's head andtorso can continue to ride down smoothly into the airbag 160 and thenenter rebound in a synchronized manner, which significantly decreasesthe possibility for injury to an occupant's neck.

The moderation of belt loads may occur approximately when the occupant'storso reaches an arrested state and is poised to transition from forwardmovement to rearward movement. Stated otherwise, the moderation of thebelt loads may occur approximately with the moment when the webbing ofthe seatbelt system has been stretched to its limit and is ready topropel the occupant rearward in the vehicle after maximum forwarddisplacement and full arrest of the occupant has occurred. As indicatedabove, this occurs towards the end of the crash pulse or crash event.

In addition to initiation of the moderation of belt loads based on atrigger such as the position of the occupant or conditions of theseatbelt system such as its load or the stretching of the seatbelt,another possible trigger is a designated time. For example, moderatingthe belt loads may occur at a designated time such as within a rangebetween about 75 milliseconds and about 200 milliseconds or betweenabout 75 milliseconds and about 200 milliseconds after an impact hasbeen sensed. The terms “about” and “approximately” as used to describethis moment during the crash event means twenty milliseconds before orafter the arrest of occupant's torso or after the seatbelt has beenstretched to its limit. As discussed in more detail below, moderatingthe belt loads may occur as a distinct transition time such that thereis an immediate step down or digression in the amount of force appliedto seatbelt 112. Additionally, the load on the seatbelt may be reducedover a short period of time leading up to the point of maximum forwarddisplacement of the occupant. The reduction of the belt load is reducedin direct relation to the occupant velocity relative to the velocity ofthe vehicle.

FIG. 1D shows the movement of the occupant's torso as a result ofrebound induced loading. During this phase, the torso continues to bemoved toward backrest 92, as shown by direction arrow, D_(T). Moreparticularly, the torso rebounds, which causes the head to nod forward,as shown by direction arrow D_(H), as the head follows the torso.

FIG. 1E shows the rebound impact loading. After the occupant impactsbackrest 92, the occupant's torso is arrested, while the occupant's headcontinues to move rearwards. Eventually, the head is arrested againstthe head restraint 96 of seat 90.

FIGS. 2-5 show four different embodiments of seat belt systemsrespectively at 310, 410, and 510. These embodiments are designed suchthat the load on the seatbelt is altered during an impact of thevehicle. As described below, various possible transitions of the load onthe seatbelt are described below with respect to the graphs provided inFIGS. 6A-6C.

FIG. 2 shows the length of seatbelt 212 that is extended, or the webpayout, to provide for the step down effect L. In one embodiment, thelength, L_(W), is achieved by a pyrotechnic or a mechanical longdigressive/adaptive load limiter switching. In another embodiment, amechanical system is used to moderate the belt loads in direct relationof the occupant velocity relative to the velocity of the vehicle. Forexample, retractor system 214, which contains one of these embodiments,may release the length L_(W).

FIG. 3 show a D-ring 316 that is configured to move a distanceidentified as L_(D). When D-ring 316 moves, there is a web payout asidentified at L_(W).

FIG. 4 shows a belt anchor 418 that is configured to move a distanceidentified as L_(B1). When belt anchor 418 moves, there is a web payoutas identified at L.

FIG. 5 shows a buckle 520 that is configured to move a distanceidentified as L_(B2). When buckle 520 moves, there is a web payoutidentified at L_(W).

Other embodiments are also possible that provide for a web payout toalter the load of the seatbelt in a seatbelt system including those thatdo not provide a web payout through a mechanical release. For example,the webbing of the seatbelt may be a material capable of stretching whena certain load is reached. As an example of such an embodiment, thewebbing may comprise a material that stretches with about 100% plasticdeformation and about 0% elastic deformation and therefore have limitedelastic induced occupant rebound from the restraint system. Such a beltsystem can moderate loads within the webbing, as described above, butthe amount of elastic energy stored in the webbing would differ. In oneembodiment, instead of just allowing the occupant to ride down with theairbag, the seatbelt may be spooled back to resume some load at theshoulder level.

These embodiments shown in FIGS. 1A-1E, FIG. 2, FIG. 3, FIG. 4 and FIG.5 can be designed such that the load on the seatbelt is altered as shownin FIGS. 6A-6C, which are graphs that show the theoretical loadingmeasured over time by a load cell positioned on the seatbelts at F₁assuming a continuous load is applied to the seat belt system. Moreparticularly, FIGS. 6A-6C show the possible loads of the embodiments ofseatbelt systems shown in FIGS. 2-5 during the five phases describedabove with respect to FIGS. 1A-1E. Note, however, that the phasescorrespond primarily with the position of the occupant, particularly theoccupant's neck, while the graphs show the load on the seatbelts. Asshown in the graphs, the configurations of these embodiments provide fora significant digression or step down in the load that is measuredduring phase 3. FIG. 6A shows that the load drops significantly at theshoulder belt and does not return to its previous level as the airbag isrelied upon for protecting the occupant and the occupant rides down withthe airbag. FIGS. 6B-6C show loads when one of the seatbelt systems 210,310, 410, and 510 are designed to operate like system 110′ is shownoperating in FIGS. 11A-11B, as described below. FIG. 6B shows that theseatbelt load again continues to drop as the occupant rides down withthe airbag. FIG. 6C shows the load being completely reduced during phase3 so that only the airbag is subsequently relied on to keep thepassenger positioned as desired.

FIGS. 7A-7B respectively provide a perspective view and a side view ofairbag 160. An airbag such as airbag 160 is generally a conventionallyconfigured airbag that may be used with the seat belt systems describedabove. Airbag 160 has a lower portion 162 and a face 166. Face 166 has abottom 164 and a top 168. Top 168 of face 166 transitions to a topportion 170. Airbag 160 may also have a fixed vent 180.

FIG. 8 is a side view of a dummy, a seat belt system and the airbagcushion depicted in FIGS. 7A-7B. FIG. 8 shows the dimensions of a dummycorresponding in size to AM50, which is a 50th percentile male dummyhaving a height of 175 cm (5′ 9″ ft) tall and a mass of 77 kg (170 lb),as identified at 80 _(AM50). The lengths from the thighs of each dummyto the top of the head of each dummy are identified in FIG. 8 at L₁. Theheight of airbag cushion 160 as measured from the lowest point on bottomportion 162 to the highest point on top portion 170 is identified atL_(A). Because L_(A) is greater than L₁, top portion 170 extends overthe occupant's head.

FIG. 9 provides a side view of another embodiment of an airbag 160′ thatmay be used with the seat belt systems as described above. Face 166′ issloped as shown so that the face 166′ is at an angle, identified as α.Angle α starts at bottom 164′ of face 166′ and extends upward to top168′ of face 166′. Top 168′ then transitions to top portion 170′. Bottomportion 162′ provides lower coverage for proper lower chest andabdominal restraint. The angle α may be any angle that matches the anglebetween the head and the torso as the head and torso are contacted bythe airbag. For example, the angle α may be up to about 36°, betweenabout 15° and about 36°, between about 20° and about 36°, between about20° and about 30°. The angle may also be about 28°.

As shown in FIG. 10, bottom 164′ of face 166′ corresponds with thelocation of an AF05 dummy's shoulder level. The dummy corresponding insize to AF05, which is a 5th percentile female dummy having a height of152 cm (5 ft) tall and a mass of 50 kg (110 lb), is identified at 80_(AF05). FIG. 10 also shows the dimensions of a dummy corresponding insize to AM50, as identified at 80 _(AM50). The lengths from the thighsof each dummy to the top of the head of each dummy are identified inFIG. 10 at L₁ and L₂ respectively for dummy 80 _(AM50) and dummy 80_(AF05). The height of airbag cushion 160′ as measured from the lowestpoint on bottom portion 162′ to the highest point on top portion 170′ isidentified at L_(A′). The height of airbag cushion 160′ as measured fromthe bottom 164′ of face 166′ to the front of the airbag cushion isidentified at L₃. In this embodiment, the length of the airbag cushion,L_(A′), is less than the length, L₁.

FIG. 10 also shows that top portion 170′, after full deployment ofairbag cushion 160′, extends to a height that is between the height ofthe top of the head of an AM50 dummy as shown by the line from the headof dummy at 80 _(AM50) at H_(AM50(h)) and the top of the head of an AF05dummy as shown by the line from the head of dummy 80 _(AF05) atH_(AF05(h)), when each dummy is in a normal seated position. Thedifference between the height of the top of the dummys' heads is shownat L_(h). Additionally, FIG. 10 shows that after full deployment of theairbag cushion 160′, while either dummy is in a normal seated position,bottom portion 162′ extends between the height of the top of the thighof dummy 80 _(AM50) and the top of the thigh of dummy 80 _(AF05), whichare respectively shown at H_(AM50(t)) and at H_(AF05(t)), as measuredfrom each dummy's knee to the top of base 94. The difference between theheight of the top of the thighs is shown at L_(t).

FIG. 11A shows an occupant or dummy 80 during rebound induced loading,which is referred to herein as phase 3, after seat belt system 110′ andairbag 160 have cooperated together to moderate the loads applied to theoccupant when a certain amount of force is applied to belt 112. Incontrast to the same phase with airbag cushion 160 as shown in FIG. 1C,the angle of sloped face 164′ allows the occupant's head to moveforward, as shown by direction arrow, D_(H).

FIG. 11B shows an occupant 80 as airbag cushion 160′ begins to deflate.Occupant 80 is shown riding the airbag down. As a result, the occupant'shead and torso continue to move forward, as shown respectively bydirection arrows, D_(H) and D_(T).

FIG. 12 is a side view of airbag 160″, which has a sloped impact face166″ like sloped impact face 166′. Airbag 160″ also has a top portion170″ that is sized and configured to prevent airbag cushion 160″ fromextending over an occupant's head. Top portion 170″ is substantiallyflat, meaning that it is relatively parallel with a longitudinal axis ofthe vehicle. Top portion 170″ also has a height, as described below,with respect to FIG. 13 that assists in preventing airbag cushion fromextending over an occupant's head. Top portion 170″ of the airbag is“flat” since the cushion depth at this point needs to be maintainedwhile minimizing the ability of the airbag to extend over the occupant'shead, particularly an AF05 dummy.

FIG. 13 shows dummy 80 _(AM50) after deployment of airbag 160″ at amoment during an impact that is similar to the moments shown in FIG. 1Cand FIG. 11A. Airbag 160″ has a height as measured from the lowest pointon bottom portion 162″ to the highest point on top portion 170″ asidentified at L_(A″) that is less than the length, as identified at L₁,from the dummy's thighs to the top of the dummy's head. Because L_(A″)is less than L₁, top portion 170″ does not extend over the occupant'shead. Note that L₁ is actually the length from the dummy's thighs to thetop of the dummy's head as measured when the dummy is in a normal seatedposition against backrest 92 as shown in FIG. 10 and not in the positionas shown in FIG. 13. While L_(A′) in FIG. 10 and L_(A″) in FIG. 13 areboth less than L₁, the length of the airbag, L_(A), may also beapproximately equal to the length, L₁ such that length L_(A) is notgreater than the length L₁. In other embodiments, such as airbag 160,L_(A) may be set such that it is only about 1 cm to about 3 cm greaterthan L₁. For such embodiments, length L_(A) is not substantially greaterthan the length L₁.

FIG. 13 also shows that the neck of dummy 80 _(AM50) is tipped forwardin the flexion mode due to sloped face 166″. This configuration matchesthe angle of the head and neck of the occupant just prior to cushionloading so as to not change or affect the neck negatively during thecrash event. Additionally, this configuration allows the head to followa natural ride-down trajectory.

EXAMPLE

Testing was conducted to identify the load some of a particular systemunder certain conditions. The results of this testing are reported inExample 1. The following specific example is included for illustrativepurposes only and is not to be considered as limiting to thisdisclosure.

Example 1

A system configured like the system as shown in FIG. 2 was tested with avehicle moving at 35 miles per hour upon impact. Loads were measured atthe shoulder portion of belt 212, as indicated at F₁; at the lap portionof belt 212, as indicated at F₂; and at retractor 214, as indicated atF₃. The results of the data are in the chart provided as FIG. 14.

As indicated above, the five phases described above with respect toFIGS. 1A-1E correspond primarily with the position of the occupant,particularly the occupant's neck. While the table reports the loads, thefive phases can also be referenced with respect to the timing identifiedin the table. During phase 1 the seatbelt interacts with the dummy untilthe airbag contacts the dummy. The transition from phase 1 to phase 2occurs during about 25-30 milliseconds after the impact is sensed andcauses the moment of the neck to move from a negative moment to apositive moment. The transition from phase 2 to phase 3 occurs duringabout 80 milliseconds after the impact is sensed and generallycorresponds with maximum forward displacement of the occupant's chest.The transition from phase 3 to phase 4 occurs about 120 millisecondsafter the impact is sensed and generally corresponds with a transitionof the neck from negative moment to a positive moment. The transitionfrom phase 4 to phase 5 corresponds with the occupant's torso impactingthe seatback.

The load sensor at the lap portion of the seatbelt, as shown at F₂, doesnot reflect a significant change during the transition from phase 3 tophase 4. However, the load sensor at the retractor and at the shoulderportion of the seatbelt as respectively shown at F₁ and F₃ showsignificant digression as the loads are moderated.

It will be understood by those having skill in the art that changes maybe made to the details of the above-described embodiments withoutdeparting from the underlying principles presented herein. For example,any suitable combination of various embodiments, or the featuresthereof, is contemplated.

Any methods disclosed herein comprise one or more steps or actions forperforming the described method. The method steps and/or actions may beinterchanged with one another. In other words, unless a specific orderof steps or actions is required for proper operation of the embodiment,the order and/or use of specific steps and/or actions may be modified.

Throughout this specification, any reference to “one embodiment,” “anembodiment,” or “the embodiment” means that a particular feature,structure, or characteristic described in connection with thatembodiment is included in at least one embodiment. Thus, the quotedphrases, or variations thereof, as recited throughout this specificationare not necessarily all referring to the same embodiment.

Similarly, it should be appreciated that in the above description ofembodiments, various features are sometimes grouped together in a singleembodiment, figure, or description thereof for the purpose ofstreamlining the disclosure. This method of disclosure, however, is notto be interpreted as reflecting an intention that any claim require morefeatures than those expressly recited in that claim. Rather, inventiveaspects lie in a combination of fewer than all features of any singleforegoing disclosed embodiment. It will be apparent to those havingskill in the art that changes may be made to the details of theabove-described embodiments without departing from the underlyingprinciples set forth herein.

The claims following this Detailed Description are hereby expresslyincorporated into this Detailed Description, with each claim standing onits own as a separate embodiment. This disclosure includes allpermutations of the independent claims with their dependent claims.Recitation in the claims of the term “first” with respect to a featureor element does not necessarily imply the existence of a second oradditional such feature or element. Elements specifically recited inmeans-plus-function format, if any, are intended to be construed inaccordance with 35 U.S.C. §112 ¶ 6. Embodiments of the invention inwhich an exclusive property or privilege is claimed are defined asfollows.

The invention claimed is:
 1. A method for reducing injury of an occupantof a vehicle in a crash event, the method comprising: deploying anairbag cushion in the vehicle in front of the occupant; activating aseatbelt system that comprises a seatbelt to restrain the occupant andact on the occupant with seatbelt loads at various locations, whereinactivating the seatbelt system comprises retracting the seatbelt viapretensioning during a pretensioner loading phase; permitting theoccupant to ride down into the seatbelt system during a ride downinduced loading phase that occurs after the airbag cushion has deployedand that follows the pretensioner loading phase; and moderating, duringan arrest and transition induced loading phase that follows the ridedown induced loading phase, the seatbelt loads acting on the occupantduring the crash event to synchronize a rebound of a torso of theoccupant from the airbag cushion and a rebound of a head of the occupantfrom the airbag cushion, which limits head and torso differentialloading by the airbag cushion and therefore limits occupant neck loads.2. The method of claim 1, wherein the moderating of the seatbelt loadsis initiated when the torso of the occupant reaches an arrested stateand is poised to transition from forward movement to rearward movement.3. The method of claim 1, wherein the moderating of the seatbelt loadsis initiated when a seatbelt of the seatbelt system has been stretchedto its limit and is ready to propel the occupant rearward in the vehicleafter maximum forward displacement and full arrest of the occupant hasoccurred.
 4. The method of claim 1, wherein the moderating of theseatbelt loads is initiated at a predetermined time.
 5. The method ofclaim 1, wherein the moderating of the seatbelt loads is initiatedwithin a range between about 40 milliseconds and about 200 millisecondsafter an impact has been sensed.
 6. The method of claim 1, wherein themoderating of the seatbelt loads results in a digression in a loadamount measured at a shoulder belt.
 7. The method of claim 1, whereinthe moderating of the seatbelt loads comprises switching a pyrotechnicload limiter.
 8. The method of claim 1, wherein the moderating of theseatbelt loads comprises moving one of a D-ring, a seatbelt anchor, or abuckle or plastically deforming a seatbelt webbing.
 9. The method ofclaim 1, wherein the airbag cushion comprises: a bottom portion; a topportion; and a sloped impact face between the bottom portion and the topportion that is configured to be directed toward the head of theoccupant when deployed, wherein the face is sloped such that a tangenttaken from the bottom of the face upward defines an angle of no greaterthan 36° relative to a vertical line.
 10. The method of claim 9, whereinthe angle is no less than 15°.
 11. The method of claim 1, wherein theairbag cushion comprises: a bottom portion; a top portion; and an impactface between the bottom portion and the top portion that is configuredto be directed toward the head of the occupant when deployed, wherein alength of the airbag cushion extending between a lowest point of thebottom portion and a highest point of the top portion is notsubstantially greater than a length from thighs of an AM50 dummy to atop of the head of an AM50 dummy when the dummy is in a normal seatedposition.
 12. The method of claim 11, wherein the face is sloped suchthat a tangent taken from the bottom of the face upward defines an anglerelative to a vertical line, and wherein a value of the angle is between15° and 36°.
 13. The method of claim 11, wherein the top portion of theairbag cushion is substantially flat such that it is substantiallyparallel with a longitudinal axis of the vehicle.
 14. The method ofclaim 11, wherein the length of the airbag cushion extending between thelowest point of the bottom portion and the highest point of the topportion is no greater than the length from the thighs of an AM50 dummyto the top of the head of the AM50 dummy when the dummy is in a normalseated position.
 15. The method of claim 11, wherein the length of theairbag cushion extending between the lowest point of the bottom portionand the highest point of the top portion is less than the length fromthe thighs of an AM50 dummy to the top of the head of the AM50 dummywhen the dummy is in a normal seated position.
 16. A method for reducinginjury of an occupant of a vehicle in a crash event, the methodcomprising: inflating an airbag cushion in the vehicle in front of theoccupant; activating a seatbelt system to restrain the occupant and acton the occupant with seatbelt loads at various locations; reducing theseatbelt loads acting on the occupant via a seatbelt load limiter as atorso of the occupant rides down into the airbag cushion; and moderatingthe seatbelt loads acting on the occupant via a web payout mechanismthat is distinct from the seatbelt load limiter to delay a rebound ofthe torso of the occupant from the airbag cushion.
 17. The method ofclaim 16, wherein the moderating of the seatbelt loads is initiated whenthe occupant's torso reaches an arrested state and is poised totransition from forward movement to rearward movement, and whereindelaying the rebound of the torso of the occupant from the airbagcushion synchronizes the rebound of the torso of the occupant from theairbag cushion and a rebound of the head of the occupant from the airbagcushion, which limits head and torso differential loading by the airbagcushion and therefore limits occupant neck loads.
 18. The method ofclaim 16, wherein the moderating of the seatbelt loads is initiated whena seatbelt of the seatbelt system has been stretched to its limit and isready to propel the occupant rearward in the vehicle after maximumforward displacement and full arrest of the occupant has occurred, andwherein delaying the rebound of the torso of the occupant from theairbag cushion synchronizes the rebound of the torso of the occupantfrom the airbag cushion and a rebound of the head of the occupant fromthe airbag cushion, which limits head and torso differential loading bythe airbag cushion and therefore limits occupant neck loads.
 19. Themethod of claim 16, wherein the moderating of the seatbelt loads isinitiated at a predetermined time.
 20. The method of claim 16, whereinthe moderating of the seatbelt loads is initiated within a range betweenabout 40 milliseconds and about 200 milliseconds after the crash eventhas been sensed.
 21. The method of claim 16, wherein the moderating ofthe seatbelt loads results in a digression in a load amount measured ata shoulder belt.
 22. The method of claim 16, wherein the seatbelt loadlimiter comprises a fold sewn into webbing of the seatbelt or an energymanagement mechanism contained in a seatbelt retractor.
 23. The methodof claim 16, wherein the reducing of the seatbelt loads via the seatbeltload limiter permits the torso of the occupant to move away from abackrest.
 24. The method of claim 16, wherein the moderating of theseatbelt loads acting on the occupant via the web payout mechanismcommences after the reducing of the seatbelt loads via the seatbelt loadlimiter is complete.
 25. The method of claim 16, wherein the moderatingof the seatbelt loads occurs after the airbag cushion has deployed. 26.The method of claim 16, wherein the moderating of the seatbelt loads isachieved via an immediate step down in the amount of force applied tothe seatbelt.
 27. The method of claim 16, wherein the airbag cushioncomprises: a bottom portion; a top portion; and a sloped impact facebetween the bottom portion and the top portion that is configured to bedirected toward a head of the occupant when deployed; wherein the faceis sloped relative to the top and bottom portions such that a tangenttaken from the bottom of the face upward defines an angle of no greaterthan 36° relative to a vertical line, and wherein delaying the reboundof the torso of the occupant from the airbag cushion synchronizes therebound of the torso of the occupant from the airbag cushion and arebound of the head of the occupant from the airbag cushion, whichlimits head and torso differential loading by the airbag cushion andtherefore limits occupant neck loads.
 28. The method of claim 16,wherein the moderating of the seatbelt loads comprises moving one of aD-ring, a seatbelt anchor, or a buckle or plastically deforming aseatbelt webbing.
 29. A method for reducing injury of an occupant of avehicle in a crash event, the method comprising: inflating an airbagcushion in the vehicle in front of the occupant; activating a seatbeltsystem to restrain the occupant and act on the occupant with seatbeltloads provided by a seatbelt at various locations; and moderating theseatbelt loads acting on the occupant during the crash event tosynchronize a rebound of an occupant torso from the airbag cushion and arebound of an occupant head from the airbag cushion which limits headand torso differential loading by the airbag cushion and thereforelimits occupant neck loads, wherein the moderating of the seatbelt loadsis achieved via an immediate step down in the amount of force applied tothe seatbelt.
 30. The method of claim 29, wherein the moderating of theseatbelt loads is initiated when the occupant's torso reaches anarrested state and is poised to transition from forward movement torearward movement.
 31. The method of claim 29, wherein the moderating ofthe seatbelt loads is initiated when a seatbelt of the seatbelt systemhas been stretched to its limit and is ready to propel the occupantrearward in the vehicle after maximum forward displacement and fullarrest of the occupant has occurred.
 32. The method of claim 29, whereinthe moderating of the seatbelt loads is initiated at a predeterminedtime.
 33. The method of claim 29, wherein the moderating of the seatbeltloads comprises moving one of a D-ring, a seatbelt anchor, or a buckleor plastically deforming a seatbelt webbing.
 34. The method of claim 29,wherein the airbag cushion comprises: a bottom portion; a top portion;and a sloped impact face between the bottom portion and the top portion,which is configured to be directed toward an occupant's head whendeployed; wherein the face has a bottom that is adjacent to the bottomportion and a top that is adjacent to the top portion, and wherein theface is sloped such that a tangent taken from the bottom of the faceupward defines an angle of no greater than 36° relative to a verticalline.